Do not intall the MSI over the 5.14.2.1 installation as automatic uninstallation does not work correctly. Uninstall the old version manually + remove all residuals (e.g. delete c:\strawberry directory) before installing this version.

The 64-bit version does not contain all of the modules that the 32-bit version does - Math::Pari (#52146) + all dependants (e.g. Module::Signature).